I bought a Crown Graphic with the 135 Optar.
It came with a flash, but it's not Graflex. It says HR on it. It appears to take 3 D cell batteries. It has 3 outlets that appear to be household. The one in front says it is for remotes The 2 on each side say nothing. It came with a household to (modern)flash sync, so I haven't determined if it works yet. The reflector is about 5-6 inches in diameter.
Anything anyone can tell me about it would be appreciated. I'll try to order a cord from Paramount to fit the double prong of my lens. Then maybe start looking for flashbulbs.
Thanks,
Matt

It is a Heiland flash, made by Heiland Research in Colorado. The reflector should be focusable so you can adjust the width of coverage to suit the subject distance. It moves in and out and locks with a thumb screw. There are reference marks to guide you, on the socket where the reflector slides. High quality unit, these. I have a couple and like them much better than any other of the period.